Characteristics and risk factors of opioid poisoning in opioid-dependent individuals using their primary opioid of dependence: a registry-based study.

BACKGROUND: Opioid addiction and poisoning are prevalent health issues in Iran, where various types of opioids are easily accessible. Despite being dependent on a specific type of opioid, some opioid-dependents abuse different types opioids which can prone them to some consequences. This study aimed to assess the characteristics and risk factors of opioid poisoning among opioid-dependent individuals poisoned by their own or opioid. METHODS: This cross-sectional study analyzed data from the MTR-MUMS-Iran (May 2021-January 2022), including opioid-dependent adults poisoned by their regularly used opioid. Opioid dependency was categorized as synthetic opioid or opiate. Data extracted included demographics, opioid type, manner of poisoning, and clinical manifestations. Also, a comparison was conducted between poisoning prevalence with 2011 Iranian Mental Health Survey (IMHS) opioid dependency data. RESULTS: Among 3064 registered cases, 116 patients with a mean age of 40.27 years were included, with a mortality rate of 1.7% (n = 2). The frequency of synthetic opioid and opiate overdose was similar (50.9% vs. 49.1%). Opium and methadone were the most common opioids involved. The most common clinical presentation was decreased level of consciousness (72.4%). Excessive use (50.9%), suicide (24.1%), were the main scenarios leading to poisoning. The manner of poisoning among elderly and opiate-dependent patients was excessive use, while younger synthetic opioid-dependent patients tended to attempt suicide. Furthermore, opiate-dependent individuals were more likely to co-ingest therapeutic medications and have underlying renal disease. The average hospital stay was 2.31 days, with age being a significant predictor of length of stay. CONCLUSION: The findings of this study suggest some practical implications for physicians. Excessive use and suicide are the two main manners of opioid poisoning among opioid dependents. Women and methadone-dependent cases are at higher risk for opioid toxicity, and buprenorphine appears to be the safest opioid option.